Critical examination of a correlation between brain gamma-aminobutyric acid (GABA) concentrations and a personality trait of extroversion in healthy volunteers as measured by a 3 Tesla proton magnetic resonance spectroscopy study.

We hypothesized that brain gamma-aminobutyric acid (GABA) levels are associated with neuroticism, a trait associated with depression and anxiety disorders. We examined the correlation between brain GABA concentrations and the five factors included in the NEO Five-Factor Inventory (NEO-FFI) in healthy volunteers using magnetic resonance spectroscopy (MRS) at 3 T. Forty-one healthy subjects (21 males, 20 females; age: 35+/-7 years) were enrolled in this study. Each subject underwent a 3T 1H-MRS study with a MEGA-PRESS sequence. Spectroscopy voxels (3 cm x 3 cm x 3 cm) were placed in the frontal lobe and the parieto-occipital lobe. A negative correlation was found between the GABA/creatine ratios in the frontal lobe and scores of extroversion on the NEO-FFI. These results suggest that GABAergic neurons are related to personality traits of healthy subjects.